4.48
pH=pKa+log([A-/HA])
25% deprotonated tells us that A- is .25 and that the rest (75% is protonated) thats .75.
4 = pKa + log

4 - log

= pKa
4.48=pKa
The number of mole of ethanol present in the beaker is 0.217 mole
Description of mole
The mole of a substance is related to it's mass and molar mass according to the following equation:
Mole = mass / molar mass
How to determine the mole of C₂H₅OH
From the question given above, the following data were obtained:
Mass of C₂H₅OH = 10 g
Molar mass of C₂H₅OH = (12×2) + (1.01×5) + 16 + 1.01 = 46.06 g/mol
Mole of C₂H₅OH =?
Mole = mass / molar mass
Mole of C₂H₅OH = 10 / 46.06
Mole of C₂H₅OH = 0.217 mole
Learn more about mole:
brainly.com/question/13314627#SPJ1
The "sub shells" are the orientations and shapes for your orbitals, going in order by Shells are a collection of subshells with the same principle quantum number, and subshells are a collection of orbitals with the same principle quantum number and angular momentum quantum number. Hope this helps :)
Planck suggested that light/energy was absorbed/released in certain amounts, called quanta.